Electric-motor car



(No Model.)

I. H. PARNHAM.

ELECTRIC MOTOR GAR.

PatentQdFeb-25Q189o.

N. Vriens, mxo-Mmmm?. wmingm. uc.

passenger sitting over the motor.-

UNITED STATES PATE- NT OFFICE.

ISAIAI-l Il. FARNHAM, OF MALDEN, ASSIGNOR OF TWOJIHIRDS TO GEO.

WILLIS PIERCE, OF BOSTON, AND ALBERT P. SAIVYER, OF NEVVBURY- PORT,MASSACHUSETTS.

ELECTRIC-MOTOR CAR.

SPECIFICATION forming part of Letters Patent No. 422,339, dated February25, 1890.

i Application filed April 1889. Serial No. 306,113. (No model.)

To all whom t may con/cern.'

Be it known that I, ISAIAH H. FARNHAM, of Malden, in the county ofMiddlesex and State of Massachusetts, have invented certain new anduseful Improvements in Electric-Motor Cars, of which the following is aspecification.

This invention has for its object the protection of watches carried bypassengers on cars which are impelled by electric motors.

It is well known that in electric-ear systems now in use each car hasone or more electric motors-f-usually two-located below the floor of thecar and Within a short distance-say thirty-six to forty inches-from thelocation of a watch on the person of a The balance and hair-spring ofthe watch are therefore brought into a strong magnetic eld, and when thehair-spring is made of steel and the balance wholly or in part of steel,as in the great majority of watches now in use, said parts becomemagnetized to such extent as i to seriously affect the time-keepingproperties of the watches thus exposed. Much complaint has been causedamong thepatrons of electric-motor cars by this disturbance oftime-pieces, and many are obliged to go to the expense of havingnon-magnetic balances and hair-springs applied to their watches.

My invention has for its object to obviate this objection by soddetlecting the lines of force radiating from the electric motor ormotors and from the conductors connecting said motors with overheadwires that watches carried by passengers within the car will be screenedand protected from such lines of force. To this end my inventionconsists in the combination, with a car and an electric motor,

of a shield of magnetic metal interposed between the motor and theportions of the interior of the car which would otherwise be within themagnetic field of said motor, said shield deiiecting the lines of forcefrom the motor toward said portions of the interior of the car, andpreventing the described injurious action on watches located therein, asI will now proceed to describe.

The accompanying drawing, forming a part of thisspeciiication,represents a side elevation and partial longitudinal section of a carprovided with my improvement.

In the drawing, a represents the body of a street-car, and b b representtwo electric motors of any suit-able construction located unl der thecar and suitably geared to the axles of the wheels thereof. The type ofmotor here shown is known as the Sprague motor;7 but it is obvious thatmy improvement may be employed with any other motor which is capable ofbeing used for this purpose.

In carrying out my invention I interppse between the motor and theinterior of the car a shield s, composed of a suitable magnetic metal,as wrought-iron. Said shield may be made of one or more sheets or layersof metal attached to any suitable part of the car. I have here shown theshield as composed of two sheets, one attached to the bottom of the carand the other between the vtop and bottom layers of the floor of thecar.

The thickness of the sheet or sheets of iron and the area of extensionof the same length- Wise and crosswise of the ear may depend on theconstructionA and location of the motor. I recommend a sheet of aboutone-sixteenth of an inch in thickness, but do not, of course, limitmyself in this particular.

I consider it advisable to give the shield sufficient area to interposeit between the motor or motors and all parts of the interior of the car,which, wit-hout said shield, would be within the magnetic iield orfields of the motor or motors. In some caseswhen two motors are employedan independent shield may be employed for each motor.

In cars in which the motor is placed above the floor of the car theshield should be in the form of a box or casing arranged to deflect orprevent the radiation of the lines of force extending laterally orhorizontally, as well as upwardly, from the motor, or in any'other'suitable way to constitute a barrier to the lines of forcebetween the motor and any part of the car where a passengers watch maybe located.

I include under the term motor the conductors t, which connect the motorproper with overhead wires through trolleys, and in cars which are thusconnected the said con- IOO duetors t, or those portions thereof whichare within or in close proximity to the interior of the car,sl1onld haveshields s of magnetic metal. Said shields may be tubes of sheetiron, orsheet-iron tapes wound spirally about the conductors, or of any othersuitable forni and construction. I have shown a portion of but one ofsaid conductors t in the drawing, and a shield s of tubular forinsurroundingr the same, said shield being extended down to the upperplate s, above referred to.

I claiml. In a ear or other vehicle, the combination of an electricmotor applied thereto, conductors extending from said motor upwardlythrough the body of the car for connecting Said niotor with thegenerator-circuit, a fiat shield or shields of magnetic metal completelyinterposed between the passenger portion or portions of the car and saidmotor,

and a tubular shield or shieldsinterposed between the passenger portionof the car and said conductors, as set forth.

2. In a car or other vehicle, the combination of an electric motorapplied thereto loelow the car, with one or more sheets or plates ofmagnetic metal interposed between the electric motor and the carloor,all substantially as shown, and for the purpose described.

In testimony whereof I have signed my name to this specification, in thepresence ot' two subscribing witnesses, this 30th day of March, A. D.1889.

ISAIAH H. FARNHAM.

Titnessesz GEo. WILLIS PIERCE, A. D. IIARRIsoN.

